KIEV, Ukraine — Ukraine’s political crisis escalated sharply Tuesday, with at least nine people reported killed and scores injured in violent, often fiery battles between anti-government demonstrators and police in Kiev.

The clashes outside parliament erupted after the opposition accused the government of ignoring its demands even after nearly three months of protests that have paralyzed the capital. It was the worst violence since the protests began in late November.

As darkness fell, opposition leaders warned that security forces may be preparing to clear a sprawling protest tent camp on Kiev’s Independence Square. Law enforcement agencies vowed to bring order to the streets and shut down subway stations in the capital.

Yet an evening deadline set by the authorities to end street clashes passed and there was no immediate action to clear the camp.

Thousands of protesters streamed to the square to defend the camp, where Orthodox priests prayed for peace.

“We see that this regime again has begun shooting people; they want to sink Ukraine in blood. We will not give in to a single provocation,” opposition leader Arseniy Yatsenyuk told the protesters. “We will not take one step back from this square. We have nowhere to retreat to. Ukraine is behind us, Ukraine’s future is behind us.”

Olha Bilyk, spokeswoman for the Kiev city police, told The Associated Press that two policemen were killed, likely by gunshot wounds, in Tuesday’s clashes and seven civilians died, including three who were shot.

Shouting “Shame!” thousands of angry protesters hurled stones at police and set trucks blocking their way on fire. Riot police retaliated with stun grenades and fired what appeared to be small metal balls, as smoke from burning tires and vehicles billowed over Kiev.

The clashes dimmed hopes for an imminent solution to the political crisis — and tensions also soared following new steps by Russia and the European Union to gain influence over this former Soviet republic.

The protests began in November after President Viktor Yanukovych froze ties with the EU in exchange for a $15 billion bailout from Russia, but the political maneuvering continued and Moscow later suspended its payments. On Monday, however, while opposition leaders were meeting with German Chancellor Angela Merkel, Russia offered a fresh infusion of the billions of dollars that Ukraine needs to keep its ailing economy afloat.

U.S. Ambassador Geoffrey R. Payatt called for dialogue, but also threatened both sides with sanctions.

“We believe Ukraine’s crisis can still be solved via dialogue, but those on both sides who fuel violence will open themselves to sanctions,” Payatt said on Twitter.